This invention relates to electromagnetic pumps of the type known as the "helical annular linear induction pump", abbreviated as HALIP. Such pumps are disclosed for example in GB No. 730,943 and GB No. 1,143,304.
Pumps according to the invention have an application in conjunction with apparatus for testing for the occurrence of sheathing failures in fuel pins of nuclear reactors cooled by liquid metal, sometimes referred to as "Failed Fuel Detection Apparatus".
The general approach to the subject of failed fuel detection in liquid metal cooled fast reactors has been to use one coolant sampling pipe for each assembly of fuel to be tested. The pipes are terminated at respective ports of a multi-port selection valve having a rotating arm with a rubbing seal which selects for measurement in sequence the coolant appearing at the ports in the valve. GB No. 1,287,536 exemplifies this approach. Wear, sealing and maintenance problems can arise.